/*
 * Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include <string.h>
#include "apps.h"
#include "progs.h"
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#ifndef OPENSSL_NO_ENGINE
# include <openssl/engine.h>
#endif

static int init_keygen_file(EVP_PKEY_CTX **pctx, const char *file, ENGINE *e);
static int genpkey_cb(EVP_PKEY_CTX *ctx);

typedef enum OPTION_choice {
    OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,
    OPT_ENGINE, OPT_OUTFORM, OPT_OUT, OPT_PASS, OPT_PARAMFILE,
    OPT_ALGORITHM, OPT_PKEYOPT, OPT_GENPARAM, OPT_TEXT, OPT_CIPHER
} OPTION_CHOICE;

const OPTIONS genpkey_options[] = {
    {"help", OPT_HELP, '-', "Display this summary"},
    {"out", OPT_OUT, '>', "Output file"},
    {"outform", OPT_OUTFORM, 'F', "output format (DER or PEM)"},
    {"pass", OPT_PASS, 's', "Output file pass phrase source"},
    {"paramfile", OPT_PARAMFILE, '<', "Parameters file"},
    {"algorithm", OPT_ALGORITHM, 's', "The public key algorithm"},
    {"pkeyopt", OPT_PKEYOPT, 's',
     "Set the public key algorithm option as opt:value"},
    {"genparam", OPT_GENPARAM, '-', "Generate parameters, not key"},
    {"text", OPT_TEXT, '-', "Print the in text"},
    {"", OPT_CIPHER, '-', "Cipher to use to encrypt the key"},
#ifndef OPENSSL_NO_ENGINE
    {"engine", OPT_ENGINE, 's', "Use engine, possibly a hardware device"},
#endif
    /* This is deliberately last. */
    {OPT_HELP_STR, 1, 1,
     "Order of options may be important!  See the documentation.\n"},
    {NULL}
};

int genpkey_main(int argc, char **argv)
{
    BIO *in = NULL, *out = NULL;
    ENGINE *e = NULL;
    EVP_PKEY *pkey = NULL;
    EVP_PKEY_CTX *ctx = NULL;
    char *outfile = NULL, *passarg = NULL, *pass = NULL, *prog;
    const EVP_CIPHER *cipher = NULL;
    OPTION_CHOICE o;
    int outformat = FORMAT_PEM, text = 0, ret = 1, rv, do_param = 0;
    int private = 0;

    prog = opt_init(argc, argv, genpkey_options);
    while ((o = opt_next()) != OPT_EOF) {
        switch (o) {
        case OPT_EOF:
        case OPT_ERR:
 opthelp:
            BIO_printf(bio_err, "%s: Use -help for summary.\n", prog);
            goto end;
        case OPT_HELP:
            ret = 0;
            opt_help(genpkey_options);
            goto end;
        case OPT_OUTFORM:
            if (!opt_format(opt_arg(), OPT_FMT_PEMDER, &outformat))
                goto opthelp;
            break;
        case OPT_OUT:
            outfile = opt_arg();
            break;
        case OPT_PASS:
            passarg = opt_arg();
            break;
        case OPT_ENGINE:
            e = setup_engine(opt_arg(), 0);
            break;
        case OPT_PARAMFILE:
            if (do_param == 1)
                goto opthelp;
            if (!init_keygen_file(&ctx, opt_arg(), e))
                goto end;
            break;
        case OPT_ALGORITHM:
            if (!init_gen_str(&ctx, opt_arg(), e, do_param))
                goto end;
            break;
        case OPT_PKEYOPT:
            if (ctx == NULL) {
                BIO_printf(bio_err, "%s: No keytype specified.\n", prog);
                goto opthelp;
            }
            if (pkey_ctrl_string(ctx, opt_arg()) <= 0) {
                BIO_printf(bio_err,
                           "%s: Error setting %s parameter:\n",
                           prog, opt_arg());
                ERR_print_errors(bio_err);
                goto end;
            }
            break;
        case OPT_GENPARAM:
            if (ctx != NULL)
                goto opthelp;
            do_param = 1;
            break;
        case OPT_TEXT:
            text = 1;
            break;
        case OPT_CIPHER:
            if (!opt_cipher(opt_unknown(), &cipher)
                || do_param == 1)
                goto opthelp;
            if (EVP_CIPHER_mode(cipher) == EVP_CIPH_GCM_MODE ||
                EVP_CIPHER_mode(cipher) == EVP_CIPH_CCM_MODE ||
                EVP_CIPHER_mode(cipher) == EVP_CIPH_XTS_MODE ||
                EVP_CIPHER_mode(cipher) == EVP_CIPH_OCB_MODE) {
                BIO_printf(bio_err, "%s: cipher mode not supported\n", prog);
                goto end;
            }
        }
    }
    argc = opt_num_rest();
    if (argc != 0)
        goto opthelp;

    private = do_param ? 0 : 1;

    if (ctx == NULL)
        goto opthelp;

    if (!app_passwd(passarg, NULL, &pass, NULL)) {
        BIO_puts(bio_err, "Error getting password\n");
        goto end;
    }

    out = bio_open_owner(outfile, outformat, private);
    if (out == NULL)
        goto end;

    EVP_PKEY_CTX_set_cb(ctx, genpkey_cb);
    EVP_PKEY_CTX_set_app_data(ctx, bio_err);

    if (do_param) {
        if (EVP_PKEY_paramgen(ctx, &pkey) <= 0) {
            BIO_puts(bio_err, "Error generating parameters\n");
            ERR_print_errors(bio_err);
            goto end;
        }
    } else {
        if (EVP_PKEY_keygen(ctx, &pkey) <= 0) {
            BIO_puts(bio_err, "Error generating key\n");
            ERR_print_errors(bio_err);
            goto end;
        }
    }

    if (do_param) {
        rv = PEM_write_bio_Parameters(out, pkey);
    } else if (outformat == FORMAT_PEM) {
        assert(private);
        rv = PEM_write_bio_PrivateKey(out, pkey, cipher, NULL, 0, NULL, pass);
    } else if (outformat == FORMAT_ASN1) {
        assert(private);
        rv = i2d_PrivateKey_bio(out, pkey);
    } else {
        BIO_printf(bio_err, "Bad format specified for key\n");
        goto end;
    }

    if (rv <= 0) {
        BIO_puts(bio_err, "Error writing key\n");
        ERR_print_errors(bio_err);
    }

    if (text) {
        if (do_param)
            rv = EVP_PKEY_print_params(out, pkey, 0, NULL);
        else
            rv = EVP_PKEY_print_private(out, pkey, 0, NULL);

        if (rv <= 0) {
            BIO_puts(bio_err, "Error printing key\n");
            ERR_print_errors(bio_err);
        }
    }

    ret = 0;

 end:
    EVP_PKEY_free(pkey);
    EVP_PKEY_CTX_free(ctx);
    BIO_free_all(out);
    BIO_free(in);
    release_engine(e);
    OPENSSL_free(pass);
    return ret;
}

static int init_keygen_file(EVP_PKEY_CTX **pctx, const char *file, ENGINE *e)
{
    BIO *pbio;
    EVP_PKEY *pkey = NULL;
    EVP_PKEY_CTX *ctx = NULL;
    if (*pctx) {
        BIO_puts(bio_err, "Parameters already set!\n");
        return 0;
    }

    pbio = BIO_new_file(file, "r");
    if (pbio == NULL) {
        BIO_printf(bio_err, "Can't open parameter file %s\n", file);
        return 0;
    }

    pkey = PEM_read_bio_Parameters(pbio, NULL);
    BIO_free(pbio);

    if (pkey == NULL) {
        BIO_printf(bio_err, "Error reading parameter file %s\n", file);
        return 0;
    }

    ctx = EVP_PKEY_CTX_new(pkey, e);
    if (ctx == NULL)
        goto err;
    if (EVP_PKEY_keygen_init(ctx) <= 0)
        goto err;
    EVP_PKEY_free(pkey);
    *pctx = ctx;
    return 1;

 err:
    BIO_puts(bio_err, "Error initializing context\n");
    ERR_print_errors(bio_err);
    EVP_PKEY_CTX_free(ctx);
    EVP_PKEY_free(pkey);
    return 0;

}

int init_gen_str(EVP_PKEY_CTX **pctx,
                 const char *algname, ENGINE *e, int do_param)
{
    EVP_PKEY_CTX *ctx = NULL;
    const EVP_PKEY_ASN1_METHOD *ameth;
    ENGINE *tmpeng = NULL;
    int pkey_id;

    if (*pctx) {
        BIO_puts(bio_err, "Algorithm already set!\n");
        return 0;
    }

    ameth = EVP_PKEY_asn1_find_str(&tmpeng, algname, -1);

#ifndef OPENSSL_NO_ENGINE
    if (!ameth && e)
        ameth = ENGINE_get_pkey_asn1_meth_str(e, algname, -1);
#endif

    if (!ameth) {
        BIO_printf(bio_err, "Algorithm %s not found\n", algname);
        return 0;
    }

    ERR_clear_error();

    EVP_PKEY_asn1_get0_info(&pkey_id, NULL, NULL, NULL, NULL, ameth);
#ifndef OPENSSL_NO_ENGINE
    ENGINE_finish(tmpeng);
#endif
    ctx = EVP_PKEY_CTX_new_id(pkey_id, e);

    if (!ctx)
        goto err;
    if (do_param) {
        if (EVP_PKEY_paramgen_init(ctx) <= 0)
            goto err;
    } else {
        if (EVP_PKEY_keygen_init(ctx) <= 0)
            goto err;
    }

    *pctx = ctx;
    return 1;

 err:
    BIO_printf(bio_err, "Error initializing %s context\n", algname);
    ERR_print_errors(bio_err);
    EVP_PKEY_CTX_free(ctx);
    return 0;

}

static int genpkey_cb(EVP_PKEY_CTX *ctx)
{
    char c = '*';
    BIO *b = EVP_PKEY_CTX_get_app_data(ctx);
    int p;
    p = EVP_PKEY_CTX_get_keygen_info(ctx, 0);
    if (p == 0)
        c = '.';
    if (p == 1)
        c = '+';
    if (p == 2)
        c = '*';
    if (p == 3)
        c = '\n';
    BIO_write(b, &c, 1);
    (void)BIO_flush(b);
    return 1;
}